1. Field of the Invention
The present invention relates to an apparatus for photodynamic therapy and photodetection, and more particularly, to an apparatus for photodynamic therapy and fluorescence detection, in which a combined light source is provided to illuminate an object body and a multispectral fluorescence-reflectance image is provided to reproduce various and complex spectral images for an object tissue, thus performing effective photodynamic therapy for various diseases both outside and inside of the body.
2. Description of Related Art
These days, diagnostic and therapeutic methods using light are widely used in the treatment of various skin diseases such as acne, chloasma, dark spots, maculae, scars, wrinkles, malignant tumors, etc.
Phototherapy devices used for medical purposes typically include a therapeutic, light source and an optical cable using an optical fiber for delivering a light beam generated from the therapeutic light source to a treatment area of a patient.
In this case, as the light source various lamps such as a halogen lamp, a xenon lamp, a metal halide lamp, a mercury lamp, etc. can be used. Various types of optical fiber light source apparatuses based on these lamps have been developed. Also, various types of apparatuses, which can provide diagnostic images for the visible or near-infrared spectral regions using these light sources, have been developed.
U.S. Pat. No. 6,766,184 discloses a method and apparatus for generating multispectral images of tissue. The apparatus includes an illumination source configured to illuminate the tissue, a detector configured to detect radiation from the tissue, and an analysis unit configured to generate a plurality of multispectral images of the tissue. The multispectral images are used as a diagnostic tool for conditions such as cervical cancer detection and diagnosis. However, in this technique, a single color CCD camera is used as the detector, which can receive only multispectral images contained in the visible spectral range by three spectral channels, and a sensor for producing near-infrared images is not included in the apparatus. Moreover, as a non-coherent light source, only a single light source (pulsed xenon flashlight) is used. Radiation from lamps and laser sources is performed by two different light guides without a collimating optics.
Thus, the above-described U.S. Pat. No. 6,766,184 has problems in that it is impossible to obtain multispectral images by four spectral channels (R, G, B, and NIR) located in the visible and near-infrared spectral ranges at the same time, and further it is impossible to control the spectral configuration of the non-coherent light source in white light illumination.
Moreover, in the case where the apparatus is used as an endoscope, there are problems in that when the illumination is performed through the two difference light guides, one of the two light guides should use the passage of the endoscope so as to deliver two light beams, which makes it difficult to perform the operation and provides different illuminations to the field of view. Moreover, since the collimating optics is not employed, non-uniform illumination is given to the field of view in a colposcope.
Meanwhile, U.S. Patent Publication No. 20080051664 discloses an optical imaging method and apparatus for in-vivo and real-time imaging of bladder cancer and determination of tumor margins. This technique is designed for interior examination of a body using an endoscope. As a detector, an on-chip charge amplification CCD camera, a monochrome camera configured to detect near-infrared images, is used. Thus, to receive two images in various spectral ranges simultaneously, other components of a sensor are used. Therefore, there are problems in that it does not provide a color video for monitoring an object tissue in white light illumination and it is impossible to obtain multispectral images in the visible and near-infrared spectral ranges. Moreover, the apparatus is configured to illuminate the object tissue from lamp and laser light sources with the aid of other light guides. Thus, when the apparatus is used as an endoscope, the instrument channel of the endoscope should be used for the light source illumination through two different light guides, and this makes it difficult to perform the endoscope operation and provides non-uniform illumination to the field of view.
U.S. Patent Publication No. 20020035330 discloses a fluorescence endoscopy video system including a multimode light source that produces light for color and fluorescence imaging modes. However, this system does not include a combined light source that can simultaneously produce wavelengths having two or more differences determined by a user and having a wide spectral range and monochromatic light spectra for photodynamic therapy and/or multispectral fluorescence and reflectance light detection. Thus, it is impossible to excite two different kinds of fluorescent materials by optimum wavelength combination. Moreover, the system does not include an optical imaging system for stereoscopic viewing and projection with an additional optical lens on both sensors of a multispectral imaging system, and thus there is no possibility of recording images under white light and fluorescence at the same time. Furthermore, since the system does not include a movable beam splitter having a dichroic mirror, there is no possibility that the dichroic mirror may be moved out of the optical path. Thus, light loss occurs under operational conditions in which only a color image sensor is used. In addition, there is no means for performing the photodynamic therapy.
Meanwhile, U.S. Pat. No. 5,571,108 discloses a binocular stereo microscope including an observation optical system that enables a direct or optical observation of an object through a TV camera. However, since the camera is disposed in one of stereo paths behind a variable power optical system, only a small amount of illumination light detected by an objective lens of the microscope reaches the camera. Thus, the stereo microscope disclosed in U.S. Pat. No. 5,571,108 has a problem in that a significant loss of optical signals emerging from the objective lens occurs.